This invention relates to a reference point data delivery device for providing vehicles running on a road with various types of information.
The situation in which a vehicle running on a road receives service information from the road through road-to-vehicle communication from beacons installed on the road is as shown in FIG. 20. Beacons 2a, 2b installed on a road 1 offer different service information respectively via a radio communication. A vehicle 3 running on the road can communicate with the beacon 2a in an area 4a, with he beacon 2b in an area 4b, and with the beacons 2a, 2b in an area 4c respectively.
The vehicle 3 has an in-vehicle unit for performing road-to-vehicle communication with the beacons 2a, 2b, and receives, when the vehicle enters a communication-enabled area, service information from each beacon through a narrow area communication. The service information offered by the beacons 2a, 2b include but are not limited thereto, information concerning an obstacle such as a disabled car or a fallen object, information concerning an upcoming surface situation of the road surface weather conditions, information concerning traffic jams, information concerning road construction, information on running restrictions, and information concerning a parking area.
With the system based on the conventional technology as described above, however, as road-to-vehicle communication is performed between beacons and a vehicle, information delivery is performed within a narrow area, and when it is necessary to provide such information as xe2x80x9cThere is a disabled car 500 m aheadxe2x80x9d for indicating a point on the road in the traveling direction, where the reference point is located cannot be understood with a beacon having a relatively wide communication-enabled area. Further, when two types of beacons 2a, 2b offer different types of service information and the communication-enabled areas overlap to some extent, a vehicle having received the service information from the beacons cannot correctly determine whether the respective service information relates to a situation in the traveling direction or not, and therefore the vehicle cannot correctly receive the service.
It is an object of the present invention to provide an on-road reference point data delivery device which can solve the problems in the conventional technology as described above and enables a vehicle running on a road to select a beacon offering information to be accessed and also to precisely identify a position indicated in the service information.
It is another object of the present invention to provide an on-road reference point data delivery device which enables a vehicle running on a road to accurately receive service information even within a very short traveling distance and also to precisely detect a reference point corresponding to the delivered service information.
To achieve the objects described above, the on-road reference point data delivery device has a reference point data delivery means, and this reference point data delivery means indicates a reference point for the service information delivered from a beacon installed on a road by means of road-to-vehicle communication, and also has a beacon identification means which selects a beacon corresponding to the delivered service information from among a plurality of beacons.
As the on-road reference point data delivery device has the configuration and especially the beacon identification means as described above, the reference point data delivery means indicates a service reference point on a road for the service information delivered from a beacon, and in addition the beacon identification means selects and communicates with a beacon delivering the service information required by a vehicle, so that the on-road reference point data delivery device can precisely identify a position indicated by the service information depending on a position where the device receives the service information from the reference point data delivery means as a reference point.
Further the on-road reference point data delivery device according to the present invention comprises a road-to-vehicle communication radio beacon having a narrow communication area in the extending direction of the road and is installed on a road for delivering at least data on a reference point distance between a reference point and a forward point indicated by forward road information concerning, for instance, a narrower road in the forward direction or an absolute position on the road to a vehicle running in the communication area on the road, and a reference marker installed within a communication area of a road-to-vehicle communication radio beacon on a road for indicating a reference point distance of a reference point for an absolute position on the actual road, while in a vehicle a reception means for receiving signals from the road-to-vehicle communication radio beacon, a reference point marker detection means, and a reference point detection means for determining that the vehicle has entered a communication area of a road-to-vehicle communication radio beacon or passed over a reference point marker, also for determining the reference point marker which the vehicle has just passed over as a reference point.
With the configuration described above, the road-to-vehicle communication radio beacon delivers at least data concerning a reference point distance up to a point indicated by forward road information such as a narrower road in the forward direction or a position on the road, and the reference point marker indicates a reference point distance or a reference point for an absolute position on the actual road, so that the vehicle receives the signals from a reception means loaded on the vehicle for receiving signals from the road-to-vehicle communication beacons and determines that the vehicle has entered a communication area of the road-to-vehicle communication beacon, recognizes with the reference point detection means that the vehicle has passed over a reference point marker, and identifies a position of the reference point marker as a reference position. Therefore, the vehicle can accurately receive service information even within a very short traveling distance and also can precisely detect a reference point corresponding to the service information.